Download Earth Resources

Earth Resources
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Geology—study of dynamic processes in the earth’s
surface & interior
Slow processes, with occasional rapid events
Geologic time
Billions of years
Change is rule, not exception
Earth
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Golf ball-ish, peanut M & M
Core, mantle, crust
Earth
Core
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Innermost zone
Intensely hot
Solid inner part
Surrounded by liquid core—molten or semi-solid material
Mantle
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Thick
Outermost—solid rock
Underneath—hot, semisolid rock, flows slowly:
asthenosphere
Asthenosphere—plastic: can be deformed
Outermost
Thinnest
Crust
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Continental crust—29% of earth’s surface
Oceanic crust—71% of earth’s surface
Geologic Processes
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Changes on crust reflect internal processes
Interior processes—changes in interior
Heat, gravity
Core cooling—heat released as inner core cools
Outer core—cools and solidifies
Asthenosphere
Geologic Processes
Convection cells—move heat and rock in conveyor belt motion—
hot rock rises, cool rock downward
 Mantle plumes—mantle rock moves upward in vertical column,
fans out
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Plate Tectonics
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Tectonic plates—solid, rigid plates: 15
Continental and oceanic crusts and outermost portion of
mantle—lithosphere
Move slowly, on asthenosphere
Range from 1 cm -> 18 cm
Move apart and slam into each other
Create mountains, ridges and trenches
Video clip
Plate Tectonics
Plate Boundaries
Divergent—plates move away
Convergent—plates pushed together
Oceanic plate runs into continental—continental over
oceanic
Subduction—distinct subduction zones
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Transform Fault—plates slide past each other
Why Study This
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Explains distribution of plant and animal life
Provides insight into distribution and location of valuable
materials
May explain mass extinctions—ocean movements, heat
redistribution
Minerals and Rocks
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Minerals—elements or inorganic compounds, natural,
regular internal crystalline structure
Rock—combination of one or more minerals, most have
more than mineral
Rock types—igneous, sedimentary, metamorphic
Igneous Rock
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Formed below or on surface
Magma rises up from mantle, cools, hardens
Granite—below
Lava—above
Bulk of crust
Covered with soil, sedimentary rocks
Source of non-fuel mineral resources
Weathering
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Exposure to air, water, temperature change, reactive
chemicals
Rock breaks down
Mechanical—no chemical change
Chemical—selective removal of components weakens
rocks
Small pieces transported by air, water gravity
Sedimentary Rock
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Formed from sediment
Weathered rock
Water, wind, gravity, ice
Deposited in layers, accumulate
Pressure & dissolved minerals bind sediment
Sandstone, shale, dolomite, limestone, lignite, bituminous
coal
Metamorphic Rock
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Preexisting rock is subjected to high temperatures, high
pressures, chemically active fluids, or combination
Change structure, physical properties, appearance
Anthracite, slate, marble
Rock Cycle
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Cycling of rock types
Millions of years
Concentrates non-renewable resources
So What?
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We use rocks and minerals—resources
Metals—lightness, strength, malleability: tools and
machines
Non-metals—salt, clay, sand, phosphates
Energy—coal, oil, natural gas, uranium
Resources
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Nonrenewable—take long time to produce
More than 100 nonrenewable resources
Ore—rock containing enough resource to make mining
profitable
USGS Nonrenewable
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Identified resource—known location, quantity & quality, or
existence based on known evidence
Reserves—identified resources usable resource extracted
profitably at today’s prices
USGS (cont’d)
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Undiscovered—potential supplies assumed to exist on
basis of geologic knowledge and theory, unknown specific
location, quantity, quality
Other—undiscovered resources and discovered resources
that are not reserves
Resource Identification
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Aerial and satellite photos
Radiation sensing
Magnetometer
Gravimeter
Seismic
Chemical analysis
Shallow deposits
Extraction
Surface mining
 Remove overburden
 Waste soil and rocks—spoils
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Extraction
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Topography and resource determine method
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Open-pit
Dredging
Area strip
Contour strip
Mountain top removal
Placer
Reclaimed mines
Expensive
Partially successful
Extraction
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Subsurface mining—deep deposits
Vertical shafts, horizontal tunnels
Less spoils
Leaves more resource behind
More expensive
More dangerous
Processing
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Remove metals by heat or chemical treatment
Heat—smelting
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Air & water pollution--sulfur
Chemical—heap-leach
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Piles of crushed rock sprayed with cyanide
Recycling
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Cheaper than mining for some minerals
Minimills—recycle iron and steel
Substitution—new materials
Environmental Impacts of Nonrenewable Mineral
Resources
Supplies of Mineral Resources
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Earthquakes
Tsunamis
Volcanoes
Mass wasting
Landslides
 Slumps
 mudslides
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Geological Hazards